From 27124aab29d54ba9f228dee18a48e903e222812a Mon Sep 17 00:00:00 2001 From: dzwdz Date: Fri, 5 Aug 2022 14:01:42 +0200 Subject: move path_simplify to shared code, move its tests to userland --- src/shared/path.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 src/shared/path.c (limited to 'src/shared/path.c') diff --git a/src/shared/path.c b/src/shared/path.c new file mode 100644 index 0000000..9d2eda3 --- /dev/null +++ b/src/shared/path.c @@ -0,0 +1,61 @@ +#include +#include +#include + +// TODO shared assert +#define assert(...) + +int path_simplify(const char *in, char *out, size_t len) { + if (len == 0) return -1; // empty paths are invalid + if (in[0] != '/') return -1; // so are relative paths + + int seg_len; // the length of the current path segment + int out_pos = 0; + bool directory = 0; + + for (size_t i = 0; i < len; i += seg_len + 1) { + assert(in[i] == '/'); + + seg_len = 0; + directory = false; + for (size_t j = i + 1; j < len; j++) { + if (in[j] == '/') { + directory = true; + break; + } + seg_len++; + } + + /* example iteration, illustrated with terrible ASCII art + * + * |i=5 |next i = i + seg_len + 1 = 10 + * v v + * /some/path/asdf + * |--| + * seg_len = 4 + * (segment starts at i+1) */ + + if (seg_len == 0 || (seg_len == 1 && in[i + 1] == '.')) { + /* // or /./ */ + directory = true; + } else if (seg_len == 2 && in[i + 1] == '.' && in[i + 2] == '.') { + /* /../ */ + directory = true; + + /* try to backtrack to the last slash */ + while (--out_pos >= 0 && out[out_pos] != '/'); + if (out_pos < 0) return -1; + } else { + /* a normal segment, e.g. /asdf/ */ + out[out_pos] = '/'; + memcpy(&out[out_pos + 1], &in[i + 1], seg_len); + out_pos += seg_len + 1; + } + + } + + /* paths to directories should have a trailing slash */ + if (directory) out[out_pos++] = '/'; + + return out_pos; +} -- cgit v1.2.3